How to use the nyoka.PMML44.process_includes.SchemaIOError function in nyoka

if sys.version_info.major == 2:
                    urllib_urlopen = urllib2.urlopen
                    urllib_httperror = urllib2.HTTPError
                else:
                    urllib_urlopen = urllib.request.urlopen
                    urllib_httperror = urllib.error.HTTPError
                try:
                    urlfile = urllib_urlopen(locn)
                    content = urlfile.read()
                    urlfile.close()
                    params.parent_url = locn
                    params.base_url = os.path.split(locn)[0]
                except urllib_httperror:
                    msg = "Can't find file %s referenced in %s." % (
                        locn, params.parent_url, )
                    raise SchemaIOError(msg)
            else:
                if os.path.exists(locn):
                    infile = open(locn)
                    unencoded_content = infile.read()
                    if sys.version_info.major == 2:
                        content = unencoded_content
                    else:
                        content = unencoded_content.encode()
                    infile.close()
                    params.parent_url = locn
                    params.base_url = os.path.split(locn)[0]
                if content is None:
                    msg = "Can't find file %s referenced in %s." % (
                        locn, params.parent_url, )
                    raise SchemaIOError(msg)
##     if content is None:

raise SchemaIOError(msg)
            else:
                if os.path.exists(locn):
                    infile = open(locn)
                    unencoded_content = infile.read()
                    if sys.version_info.major == 2:
                        content = unencoded_content
                    else:
                        content = unencoded_content.encode()
                    infile.close()
                    params.parent_url = locn
                    params.base_url = os.path.split(locn)[0]
                if content is None:
                    msg = "Can't find file %s referenced in %s." % (
                        locn, params.parent_url, )
                    raise SchemaIOError(msg)
##     if content is None:
##         msg = "Can't find file %s referenced in %s." % (
##             locn, params.parent_url, )
##         raise SchemaIOError(msg)
    return content